What happened
The aircraft experienced a mechanical failure involving the fuel system of the left engine during flight operations. Evidence indicated that maintenance personnel had failed to properly tighten a fuel line connected to the fuel pressure switch on the left engine. This improper installation resulted in a continuous leak of fuel into the engine compartment while the aircraft was airborne.
The leaking fuel ignited, causing an inflight fire within the engine bay. The fire burned through a fuel crossfeed line, creating a situation where fuel continued to flow uncontrollably. Despite the pilot's attempts to manage the situation, the crossfeed fuel line could not be shut off by the pilot. As the situation deteriorated, the aircraft entered a left wing low attitude and ultimately contacted water. The impact forces caused the aircraft to cartwheel upon hitting the surface.
The investigation
Investigators examined the wreckage and maintenance records to determine the sequence of events leading to the accident. The primary focus was on the fuel system components, specifically the fuel pressure switch and associated lines on the left engine. Analysis confirmed that the fuel line had not been tightened during previous maintenance, allowing fuel to escape into the hot engine compartment.
Findings
The investigation concluded that the root cause of the accident was a fuel leak originating from an improperly installed fuel line at the fuel pressure switch on the left engine. This leak led to an inflight fire that compromised the fuel crossfeed system. The inability to shut off the fuel flow exacerbated the emergency, contributing to the loss of control and subsequent water impact.
Safety message
Proper installation and torque verification of fuel system components are critical for flight safety. Maintenance personnel must ensure all connections are secure to prevent leaks that can lead to fires or other catastrophic failures.